1. Field of the Invention
The present invention relates to the field of Internet Protocol Multimedia Subsystem (IMS) communication sessions and, more particularly, to invoking multiple Session Initiation Protocol (SIP) based services during a single communication session using resource lists.
2. Description of the Related Art
A demand for multimedia and data services across a broad range of communication devices has grown tremendously over the last few years. Mobile telephony devices, for example, commonly implement video on demand services, teleconferencing, dynamic movie sharing, co-browsing, music playing services, TV streaming services, and the like. A majority of the services for mobile devices are based upon a standardized architecture called the Internet Protocol (IP) Multimedia Subsystem (IMS). IMS is a flexible architecture, which is not limited to mobile devices, that is designed to permit a creation and delivery of real time multimedia services, which are independent of access media. IMS is based upon the Session Initiation Protocol (SIP), which is increasingly being used for a myriad of communications that amongst others includes Voice over Internet Protocol (VoIP) communications.
One current challenge with providing SIP based (IMS compliant) services involves invoking two or more different services during a common communication session. For example, an interactive video game provided as a SIP based service can be played from a graphical user interface (GUI) of a communication device, while a real-time communication channel (e.g., a different SIP based communication service) is concurrently active that permits game players to text or voice communicate with each other. In another example, a global positioning system (GPS) and media playing equipped smart phone can simultaneously utilize a navigation service and an audio streaming service, both of which are concurrently activate-able SIP based services.
Currently, developers often define an Extensible Markup Language (XML) schema for handling multiple services during a single communication session. Others simply pass text based data attachments within the actual SIP messages. Custom XML messages must be developed for each service of the defined schema. Thus, custom code must be written each time a new application that accesses multiple SIP based services is deployed. A need for customized code negates many of the advantages (e.g., independence of IMS services and access media) inherent in a standards based architecture, such as IMS. That is, using a set of application specific messages and an application specific schema results in a tightly coupled end product, where services are coupled to the application that invokes them. What is needed is a new, loosely coupled, standardized technique for concurrently invoking multiple SIP based services.